It is well known that aeration of fluids will lead to the multiplication of microorganisms such as bacteria, fungi, and/or protozoa. These microorganisms are hereinafter referred to as "biocatalysts". The metabolic activity of these leads to the cleaning of the fluid, i.e. the oxidation of organic matter dissolved or suspended in the fluid.
Aeration is generally carried out by injecting air under pressure into the water to form bubbles or by allowing water to flow rapidly on and/or through surfaces or substrates. Accordingly, efficient and reliable aerating equipment is required to adequately aerate large volumes of fluids such as in a modern waste treatment plant. Current practice is to direct air into holding lagoons or tanks as bubbles so that they will pass upwards through the body of liquid and thereby oxidize any suspended organic matter.
This process is not entirely satisfactory since such aeration devices are often complex and rapidly become clogged due to suspended particulate material. Moreover, the mere presence of increased amounts of air will not always guarantee appropriate growth conditions for a particular biocatalyst. Rapid evolution of bubbles from an air pump will often dislodge microorganisms attached to solid surfaces, thus defeating the intended purposes of the aeration.